The parent applications disclose a document management system that is described, in part, by the following example:
An Excel spreadsheet is printed onto paper, and the paper becomes buried in a stack of clutter on an office worker's desk. Months later the spreadsheet again becomes relevant and is dug out of the stack. Changes need to be made to the data, but the file name has long-since been forgotten. A worker simply holds the dug-out page in front of a camera associated with a desktop computer. A moment later, the electronic version of the file appears on the worker's computer display.
When the page was originally printed, tiny droplets of ink or toner were distributed across the paper in a pattern so light as to be essentially un-noticeable, but which steganographically encoded the page with a plural-bit binary number (e.g., 64 bits). A database (e.g., maintained by the operating system, the Excel program, the printer driver, etc.) stored part of this number (e.g., 24 bits, termed a UID) in association with the path and file name at which the electronic version of the file was stored, the page number within the document, and other useful information (e.g., author of the file, creation date, etc.).
The steganographic encoding of the document, and the updating of the database, can be performed by the software application (e.g., Excel). This option can be selected once by the user and applied thereafter to all printed documents (e.g., by a user selection on an “Options” drop-down menu), or can be presented to the user as part of the Print dialog window and selected (or not) for each print job.
When such a printed page is later presented to the camera, the computer automatically detects the presence of the encoded data on the page, decodes same, consults the database to identify the file name/location/page corresponding to the 24-bit UID data, and opens the identified file to the correct page (e.g., after launching Excel). Voila!
Sometimes there may be several different responses that are possible or appropriate for the encoded object. In the case of a printed office document, for example, one response may be as described above—to present the electronic version of the file on a computer, ready for editing. But other responses may also be desired, such as writing an email message to the author of the printed document, with the author's email address already specified in the message address field, etc. Various ways of selecting between such options are disclosed.
The parent applications note that such systems can be effected not just with steganographic encoding (e.g., digital watermarks), but other encoding as well—e.g., bar codes.
In the discussion that follows, the present specification expands and enhances the concepts introduced in the parent applications.